Hydraulic motor or pump device



July 8, 1969 HYDRAULIC MOTOR OR PUMP DEVICE Filed May 4, 1967 Sheet of 5INVENTOR.

ROBERT T. EDDY ATTORNEY y 8, 1969 R. T. EDDY HYDRAULIC MOTOR 0R PUMPDEVICE Sheet of 5 Filed May 4, 1967 FIG. 4

8 mm Cu INVENTOR.

ROBERT r. EDDY BY ATTORNEY V July 8; 1969 EDDY 3,453,966

I HYDRAULIC MOTOR on PUMP DEVICE Filed May 4, 1967 Sheet 3 of 5INVENTOR.

08E RT T. E D DY A RNEY. V

' July '8, 1969 v R. 1-. E DY 3,453,966

HYDRAULIC MOTOR 0R PUMP DEVICE Filed May 4, 1967 Sheet 4 of 5 l1 ill/?INVENTOR.

ROBERT T. EDDY ATTORNEY J ly 1969 R. T. EDDY HYDRAULIC MOTOR 0R PUMPDEVICE Sheet Filed May 4, 1967 FIG.

INVENTOR.

ROBERT 1; EDDY BY ATTORNEY United States Patent 3,453,966 HYDRAULICMOTOR 0R PUMP DEVICE Robert T. Eddy, South Bend, Ind., assignor to TheReliance Electric and Engineering Company, a corporation of Ohio FiledMay 4, 1967, Ser. No. 636,126 Int. Cl. F04c 1/16, 1/02, 3/00 US. Cl.103--130 20 Claims ABSTRACT OF THE DISCLOSURE Hydraulic motors and pumpsutilizing inner and outer gerotor elements are extensively used in avariety of hydraulic systems, and in recent years the gerotor principlehas been extensively used in motors and pumps in which the outer gerotorelement is stationary and the inner gerotor element, normally having oneless tooth than the outer element, is orbited within the outer elementin meshing relation therewith. The inner orbiting element is connectedby a universal joint to a rotating shaft serving as a force input oroutput member, depending upon whether the unit is being used as a motoror a pump. Inlet and outlet ports for the hydraulic fluid aresynchronized with the expanding and contracting chambers between thelobes on the two gerotor elements by a rotary valve structure operatedin accordance with the speed of the aforementioned shaft. The usual typeof motor embodying the orbital principle, while having high torqueoutput and high volumetric efliciency at low speeds, contains a valvingstructure and universal drive interconnecting the inner element with theoutput shaft of relatively complicated construction which is costly tomanufracture and which lacks the necessary or desired compactness for aneflicient and effective compound multiplestage motor. Pumps involvingthe same valving arrangement and universal joint structure have the sameinherent disadvantages as those present in motors of this type, alongwith the presence of a pulsating component in the delivery of fluid fromthe pump. It is therefore one of the principal objects of the presentinvention to provide a hydraulic motor or pump having an outer gerotorelement and a plurality of inner gerotor elements, in which the force istransmitted directly between a central rotating shaft and the innerelement without the use of a universal drive or complicated valving, andin which there is a smooth, non-pulsating flow of fluid.

Another object of the invention is to providea motor and pump structurehaving three or more gerotor elements, in which an inner non-orbitinggerotor element is meshed in driving or driven relation with anintermediate element, which in turn is meshed in driving or 3,453,966Patented July 8, 1969 driven relation with the outer gerotor element,thus forming a compound motor or pump transmitting the driving or drivenforce directly to or from a single, non-orbiting rotating shaft mountedcentrally in the motor or pump unit.

Still another object of the invention is to provide a relatively simpleand compact orbital type gerotor motor or pump in which a rotatingmanifold contains constantly open fluid inlet and outlet portscommunicating, respectively, with the expanding and contracting fluidchambers between the gerotor elements and continuously with fixed inletand outlet passages in the motor or pump housing, and in which novalving is used to obtain proper and effective fluid flow to and fromthe appropriate chambers.

A further object is to provide a motor or pump structure of theaforesaid type involving the use of three or more gerotor elements inorbiting relationship to one another, which are driven relative to oneanother by direct mechanical force and/or by hydraulic fluid reac tionto produce a speed variation and mechanical advantage between two ormore of the elements.

Another object is to provide a compound or multiple stage motor or pumpof the gerotor type in which the one gerotor element is common to morethan one operating stage or motor-pump unit.

Additional objects and advantages of the invention will become apparentfrom the following description and accompanying drawings, wherein:

FIGURE 1 is a plan view of the present motor or p p;

FIGURE 2 is a side elevational view of the motor or [FIGURE 3 is across-sectional view of the motor or pump shown in FIGURE 1, the sectionbeing taken on line 3-3 of the latter figure;

FIGURE 4 is a vertical cross-sectional view of the motor or pump, thesection being taken on line 44 of FIGURE 3;

FIGURE 5 is a cross-sectional view of the motor or pump, taken on line5-5 of FIGURE 3;

FIGURE 6 is a cross-sectional view taken on line 6--6 of FIGURE 3;

FIGURE 7 is a cross-sectional view taken on line 7-7 of FIGURE 3;

FIGURE 8 is a cross-sectional view taken on line 8--8 of FIGURE 5; and

FIGURES 9 and 10 are cross-sectional views of a modified form of a portplate used in a multiple stage motor or pump.

Referring more specifically to the drawings and to FIGURES 1, 2 and 3 inparticular, numeral 10 designates generally a motor or pump having ahousing 12 consisting of outer sections 14 and 16 and intermediatesections 18 and 20 interposed between the two outer sections and heldfirmly therebetween by a plurality of screws 22 extending through boresin the outer section 16 and two intermediate sections into threadedbores 24 in outer section 14, the screws retaining the four sectionsfirmly together to form a unitary structure. The present hydraulicstructure may be used equally as well for a motor or a pump, withoutalteration of the internal structure thereof, and this type has a widevariety of uses, particularly as a motor. However, for convenience ofthe description, the structure will be described with reference to itsuse as a hydraulic pump having fluid inlet port 26 and fluid outlet port28 in housing section 14, the pump being driven by a motor connected toinput shaft 30 journalled in bearings 31 and 32 at the axial center ofhousing 12. The pump may be driven by a direct drive coupled to theshaft, or by a belt and a sheave mounted on said shaft and keyed theretoby a key and keyway in the outer end of shaft 30. In the event thedevice is used as a motor, the inlet 26 and outlet 28 may be eitherfluid inlet or outlet, and shaft 30 becomes a power output shaft. Whilethe present mechanism is designed primarily for use with hydraulicfluids, it may be satisfactorily used in connection with other types offluid, including water,

fuel and lubricating oil, these various uses and adaptations beingconsidered Within the scope of the present invention.

The pump housing 12 contains a chamber 33 in which is disposed aninternally toothed gerotor element 34 having thirteen teeth 36 definingthe external wall of the pumping chamber. Element 34 is held securely infixed position in chamber 33 and is concentric with shaft 30. Mounted onshaft 30 is an inner gerotor element 40 secured to the shaft forrotation therewith by a key 42 in keyways 44 and 46 in the inner element40 and shaft 30, respectively, and having six external teeth 48. Theinner element is substantially on a plane with the outer gerotorelement; however, as shown in the drawings, it is offset axially forreasons more fully explained hereinafter. Interposed between outerelement 34 and inner element 40 is an intermediate gerotor element 50having teeth 52 on its outer peripheral surface and teeth 54 on itsinner peripheral surface. The number of teeth 52 on the outer peripheralsurface is one less than the number of internal teeth 36 on element 34.Likewise, the number of teeth on the inner periphery of element 50 isone more than the number of external teeth on inner element 40. There isalso a relationship between the number of teeth 52 on the periphery ofintermediate element 50 and external teeth 48 on inner element 40, thenumber on the latter element being one-half the number of teeth 52.Rotation of inner element 40 by shaft 30 causes teeth 48 of element 40to engage the respective adjacent teeth 54 of element 50, thereby movingintermediate element 50 in an orbital cycle about the internal peripheryof element 34. For each rotation of shaft 30 and inner element 40,element 50 completes four orbital cycles, and during each orbital cycleof intermediate element 50 driven by counterclockwise rotation of shaft30 as viewed in FIGURE 4, cavities 60, consisting of one-half of thecavities defined by the internal periphery of element 34 and theexternal periphery of intermediate element 50, are expanding, andcavities 62, consisting of the remaining cavities between the twoelements, are contracting, thus producing a pumping action with theexpanding cavities 60 drawing in the fluid and the contracting cavities62 expelling the fluid under pressure.

In the gerotor element arrangement just described, the expanding andcontracting chambers 60 and 62 shift around the internal periphery ofelement 34 as element 50 orbits within element 34. These expanding andcontracting chambers are connected with inlet and outlet ports 26 and28, respectively, by a rotatable port plate 70 and annular passages 72connected with inlet passage 26 and annular passage 74 connected withoutlet passage 28. The port plate is freely rotatable on shaft 30 andwithin housing section 18, and is driven by engaging cam surface 76 onthe intermediate gerotor element 50 and cam surface 78 on the portplate. Cam surface 76 on the intermediate element is concentric with theinner and outer peripheries of the element, and cam surface 78 iseccentric with respect to shaft 30 and center opening 80 through whichthe shaft passes and in which the shaft rotates. With passage 26 servingas the fluid inlet passage of the pump, the expanding cavities areconnected through the port plate to annular passage 72 by arcuate slot82, and a plurality of radially extending small passages 84 connectingthe arcuate slot with an annular passage 86 around the periphery of theport plate, annular passage 86 being defined by the external peripheryof the port plate, the internal periphery of housing section 18 and thecorresponding side of housing section 20. Annular passage 86communicates directly and continuously with passage 72 so that fluidenters the expanding cavities of the pump through inlet passage 26,annular passages 72 and 86, radial holes 84 and arcuate slot 82. Thecontracting fluid cavities are connected with outlet passage 28 byarcuate slot 90, annular grooves 92 and 93, each extending completelyaround one side of the port plate and communicating with annular passage74, which, in turn, communicates with outlet passage 28. The cam onintermediate element 50 rotates the port plate at the orbital rate ofthe intermediate element so that slots 82 and are always synchronizedwith the expanding and contracting cavities 60 and 62. The port plate issubstantially balanced hydraulically on opposite sides by a passage 95extending therethrough. If the shaft 30 is rotated in the oppositedirection, inlet and outlet ports 26 and 28 become outlet and inletports, respectively, and the fluid flows through the pump passages andslots in the opposite direction.

In the operation of the present device as a pump, if shaft 30 is drivenin the counterclockwise direction as viewed in FIGURE 4, inner gerotorelement 40 imparts an orbital movement to element 50, thereby expandingchamber 60 and contracting chambers 62 which orbit along withintermediate element 50. As element 50 moves through its orbital cycle,cam surface 76 on element 50 by engagement with cam surface 78 on portplate 70, causes the port plate to rotate at the orbital speed ofelement 50, thus maintaining slot 82 in synchronous relation with theexpanding cavities 60 and slot 90 in synchronous relation with thecontracting cavities 62. As the intermediate element 50 orbits and portplate 70 rotates, fluid is drawn in through inlet passage 26, annularpassages 72 and 74, and radial holes 84 to slot 82 and thence into theexpanding cavities 60, and when these expanding cavities with the fluidbecome contracting cavities 62 the fluid is forced therefrom throughslot 90, groove 93, annular passage 74 and outlet passage 28.

In order to use the device as a motor, the pressurized fluid isdelivered to the present outlet passage 28 and then through therespective passages to cavities 62 which then become expanding chambersand cavities 60 become contracting chambers, discharging the fluidthrough the respective passages to present inlet passage 26 whichbecomes an outlet for the driving fluid. As this operation takes place,the fluid imparts an orbital movement to intermediate element 50 whichin turn drives inner element 40 and shaft 30, which now becomes anoutput shaft for the motor.

In the embodiment of the invention illustrated in the drawings, thefluid pressure in the expanding and contracting cavities between theinner and intermediate elements 40 and 50 is balanced through annularspace 96 in chamber 33, the inner element being held, in its position onthe shaft by a snap ring 98 on shaft 30. The inner gerotor element,which has one less tooth than the internal periphery of the intermediateelement, provides a difference between the rotational speed of theintermediate element 50 and rotational speed of shaft 30, and, byincreasing or decreasing the number of teeth on elements 40 and 50 whilemaintaining a difierence of one tooth between these elements, variousdesired ratios in speed may be obtained between the intermediate elementand the shaft.

The device, as shown in the drawings, may be modified to include asecond or compound port plate as a part of the original port plate or asa separate port plate, containing inlet and outlet ports communicatingwith the expanding and contracting cavities between the inner element 40and the intermediate element 50, thus resulting in a compound motor orpump in which the stages are arranged on substantially the same radialplane. A suit able compound motor or pump structure is illustrated inFIGURES 9 and 10 showing a port plate having the same passages and slotsin the outer portion as port plate 70 and hence like numerals will beused to identify like parts in that portion of the plates. In themodified port plate 108, inner arcuate slots 110 and 112 are connectedby passages 114 and 116 to slots 82 and 90, respectively, and are inconstant communication with the respective expanding or contractingcavities between elements 40 and 50. In this embodiment a plate or otherfiller structure is employed to prevent communication between theexpanding and contracting cavities through space 96 of chamber 33, sothat the inner and intermediate gerotor elements form an effective motoror pump for augmenting the drive or output of the intermediate and outergerotor elements described hereinbefore. For example, in using thedevice as a pump and assuming port 26 is the inlet, fluid is drawnthrough slot 110 into the expanding cavities between elements 40 and 50'and is forced therefrom by the contracting cavities through slot 112,passage 116 and slot 90 into outlet 28. This compound arrangement can bemade without appreciably increasing the size of the pump housing andwith only a small increase in the number of parts. While only two stageswould be created by the arrangement described, additional stages may beadded by following the basic concept described herein.

In both the original embodiment and in the modified form, the flow orfluid may be in either direction between passages 26 and 28 dependingupon the direction of rotation of shaft 30 when the device is used as apump, and in either direction to give the desired direction of shaftrotation when the device is being used as a motor. Reference to passage26 as an intake passage has been made merely for convenience inillustrating the construction and operation of the present device whichmay be used without modification as either a motor or pump.

Two embodiments of the present motor or pump have been described indetail herein; however, various other changes and modifications may bemade without departing from the scope of the invention.

I claim:

1. A motor or pump device comprising a housing hav ing two fluidpassages, an internally toothed outer gerotor element, an externallytoothed inner gerotor element disposed within said outer gerotor elementon a common axis therewith, an externally and internally toothedintermediate gerotor element disposed between said outer and innergerotor elements for relative orbital movement in operative engagementtherewith and forming expanding and contracting chambers therebetween,the number of external teeth on said intermediate and inner elementsbeing less than the number of internal teeth on said outer andintermediate elements respectively, a shaft connected to said innergerotor element, said inner gerotor element transmitting a driving forcebetween said intermediate element and said shaft, and means forcontinually con necting a portion of the cavities between the outer andintermediate elements with one of said fluid passages and anotherportion of said cavities with the other of said fluid passages.

2. A motor or pump device as defined in claim 1 in which said outergerotor element is fixed with respect to the housing and the innergerotor element is rotatable on a fixed axis.

3. A motor or pump device as defined in claim 2 in which said innergerotor element is mounted on a rotataable shaft journalled in saidhousing.

4. A motor or pump device as defined in claim 1 in which the number ofexternal teeth on said intermediate gerotor element is one less than theinternal teeth on the outer gerotor element.

5. A motor or pump device as defined in claim 1 in which the number ofteeth on said inner gerotor element in one less than the number ofinternal teeth on said intermediate gerotor element.

6. A motor or pump device as defined in claim 1 in which the chambersbetween the outer and intermediate gerotor elements form fluid intakeand output cavities and the chambers between the intermediate gerotorelement and the inner gerotor element form cavities for fluid ofsubstantially uniform pressure.

7. A motor or pump device as defined in claim 1 in which the means forcontinually connecting the cavities with the fluid passages consists ofa rotatable generally disc-shaped port plate rotating at the orbitalspeed between said outer and intermediate gerotor elements.

'8. A motor or pump device as defined in claim 2 in which the means forcontinually connecting the cavities with the fluid passages consists ofa rotatable generally disc-shaped port plate rotating at the speed ofthe orbital movement of said intermediate gerotor element.

9. A motor or pump device as defined in claim 7 in which said port plateincludes two substantially diametrically opposed arcuate salts, and apassage connected to one of said arcuate slots and communicating withone of said fluid passages and a passage connected to the other of saidslots and communicating with the other of said passages.

10. A motor or pump device as defined in claim 9 in which an annularpassage in said housing is disposed around the periphery of said portplate and communicatingwith one slot, and a second annular passage insaid housing is disposed along the side of said port plate andcommunicating with the other of said slots.

11. A motor or pump device as defined in claim 1 in which a means isincluded for continually connecting a portion of the cavities betweenthe inner and intermediate gerotor elements with one passage and forcontinually connecting another portion of said cavities between theinner and intermediate gerotor elements with the other passage.

12. A motor or pump device as defined in claim 11 in which said outergerotor element is fixed with respect to the housing and the innergerotor element is rotatable on a fixed axis.

13. A motor or pump device as defined in claim 12 in which said innergerotor element is mounted on a rotatable shaft journalled in saidhousing.

14. A motor or pump device as defined in claim 7 in which said portplate in driven by a. cam operatively connected to said intermediategerotor element.

15. A motor or pump device as defined in claim 1 in which the innergerotor element has one half as many external teeth as the intermediategerotor element.

16. A motor or pump device as defined in claim 1 in which the means forcontinually connecting a portion of the cavities between the outer andintermediate elements with one of the fluid passages and another portionof said cavities with the other of said fluid passages includes a meansfor connecting a portion of the cavities between the inner andintermediate elements with one of said fluid passages and anotherportion of said cavities between the inner and intermediate elementswith the other of said fluid passages.

17. A motor or pump device as defined in claim 1 in which a means isincluded for connecting a portion of the cavities between the inner andintermediate elements with one of said fluid passages and anotherportion of said cavities with the other of said fluid passages.

18. A motor or pump device as defined in claim 17 in which the meansconnecting the cavities between the inner and intermediate elementsconsists of a rotatable plate.

19. A motor or pump device as defined in claim 9 in which said portplate contains two additional substantially diametrically oppositearcuate slots within the confines of said first mentioned arcuate slots.

20. A motor or pump device as defined in claim 19 in which passagesinterconnect each inner arcuate slot with the opposite outer arcuateslot.

References Cited UNITED STATES PATENTS Feuerheerd 103-130 Charlson103-131 XR Mosbacher 103-130 XR Huber 91-56 5 \VILLIAM L. FREEH, PrimaryExaminer.

WILBUR J. GOODLIN, Assistant Examiner.

US. Cl. X.R. 103-126

